Drug metabolism is an important process in the body involved in drug elimination as well as in activation of some compounds & the consequential development of toxicities. This project is designed to investigate the potential use of Flubiprofen as a selective probe of CYP2C9 & the possibility of incorporating it into an already developed 5 drug cocktail. The objective is to be able to use it in large population studies to assess the role of CYP2C9 in the pathogenesis or prognosis of diseases.